Wireless networks, as standardised by the Institute of Electrical and Electronics Engineers (IEEE) in their document 802.11, consist of a number of nodes that transmit units of data called frames on a shared radio channel. Only one node can transmit at once and the allocation of the channel to an individual node, so that it can transmit a frame, is handled by an algorithm specified by the standard.
Each frame consists of header information, optionally followed in time by a payload. The payload is the data which the network was designed to transport from node to node. The header contains the frame type (which describes the frame's role in the protocol), information about the length of the frame, an address field that identifies the intended recipient(s) of the frame and other information required for the correct operation of the protocol.
Stations in an IEEE 802.11 wireless network have hardware for the transmission and reception of the radio signals specified by the standard. This hardware can, in general, only be used on a single radio channel at once. In addition, most hardware of this type has the facility to be switched off when not in use, in a process substantially reducing the power consumption. As wireless LANs are often used in battery powered devices, any mechanism for reducing power consumption is extremely desirable.
It is accordingly an object of the present invention to address such power consumption issues.